Quantum dot color filter and display device including the same

ABSTRACT

A display apparatus includes a blue light blocking layer to block a blue light which is not converted by a color conversion layer, and a reflection preventing layer over the blue light blocking layer to prevent reflection of external light incident thereon.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2016-0020675, filed on Feb. 22, 2016,in the Korean Intellectual Property Office, and entitled: “Quantum DotColor Filter and Display Device Including the Same,” is incorporated byreference herein in its entirety.

BACKGROUND

1. Field

One or more example embodiments relate to a quantum dot color filter anda display apparatus including the same.

2. Description of the Related Art

A liquid crystal display apparatus includes two display platesrespectively including electric field generating electrodes, e.g., apixel electrode and a common electrode, and a liquid crystal layerinterposed between the two display plates. During operation of theliquid crystal display apparatus, a voltage is applied to the electricfield generating electrodes to generate electric fields in the liquidcrystal layer so that liquid crystal molecules of the liquid crystallayer are oriented according to the generated electric fields, and animage is displayed by controlling the polarization of an incident light.

When the liquid crystal display apparatus includes color filters togenerate color light, an amount of the light from a backlight source isreduced to about one third (⅓), resulting in low light efficiency. Aphoto-luminescent liquid crystal display apparatus (PL-LCD) has beendeveloped to compensate for the low light efficiency and to improvecolor reproduction characteristics. The PL-LCD is a type of liquidcrystal display apparatus in which a quantum dot color conversion layer(QD-CCL) is used instead of a conventional color filter is replacedwith. The PL-LCD displays a color image using visible light generated bya color conversion layer when light of a low wavelength band, e.g.,infrared light or blue light, is used a backlight source.

SUMMARY

According to one or more example embodiments, a display apparatus mayinclude a backlight, a liquid crystal panel provided over the backlight,and a quantum dot color filter provided over the liquid crystal panel.The quantum dot color filter may include a first color conversion layerin a first pixel area and including a plurality of quantum dots toconvert an incident light into a first color light, a second colorconversion layer in a second pixel area and including a plurality ofquantum dots configured to convert an incident light into a second colorlight, a blue light blocking layer including a first blue light blockingportion over the first color conversion layer to block emission of ablue light of the incident light which is not converted by the firstcolor conversion layer, and a second blue light blocking portion overthe second color conversion layer to block emission of the blue light ofthe incident light which is not converted by the second color conversionlayer, and a reflection preventing layer including a first reflectionpreventing portion over the first blue light blocking portion to preventreflection of external light incident thereon, and a second reflectionpreventing portion provided over the second blue light blocking portionto prevent reflection of external light incident thereon.

According to one or more example embodiments, the reflection preventinglayer may prevent reflection of blue light of external light incidentthereon.

According to one or more example embodiments, the reflection preventinglayer may include a plurality of layers having different reflectiveindices and stacked therein, and the reflective indices of the pluralityof layers may become greater as the respective one of the plurality oflayers is closer to the blue light blocking layer.

According to one or more example embodiments, the backlight apparatusmay emit blue light to be blocked by the blue light blocking layer.

According to one or more example embodiments, the blue light blockinglayer may include a plurality of first and second layers which arealternately stacked and include different reflective indices.

According to one or more example embodiments a transmittance of the bluelight blocking layer with respect to blue light emitted from thebacklight may be equal to or less than 1%.

According to one or more example embodiments, the quantum dot colorfilter may further include a dispersion material layer provided in athird pixel area.

According to one or more example embodiments, the reflection preventinglayer may further include a third reflection preventing portion providedover the dispersion material layer to prevent reflection of an externallight incident from the outside thereof.

According to one or more example embodiments, the display apparatus mayfurther include a transparent substrate over the quantum dot colorfilter, wherein the first reflection preventing portion of thereflection preventing layer may be between the transparent substrate andthe first blue light blocking portion, and the second reflectionpreventing portion of the reflection preventing layer may be between thetransparent substrate and the second blue light blocking portion.

According to one or more example embodiments, the display apparatus mayfurther include a transparent substrate provided over the quantum dotcolor filter, wherein the transparent substrate may be between the firstreflection preventing portion and the first blue light blocking portion,and between the second reflection preventing portion of is between thetransparent substrate and the second blue light blocking portion.

According to one or more example embodiments, the first reflectionpreventing portion and the second reflection preventing portion may bespaced apart from one another.

According to one or more example embodiments, a quantum dot color filtermay include a first color conversion layer provided in a first pixelarea and including a plurality of quantum dots configured to convert anincident light into a first color light, a second color conversion layerprovided in a second pixel area and including a plurality of quantumdots configured to convert an incident light into a second color light,a blue light blocking layer including a first blue light blockingportion provided over the first color conversion layer to block emissionof a first blue light of the incident light which is not converted bythe first color conversion layer, and a second blue light blockingportion over the second color conversion layer to block emission of thefirst blue light of the incident light which is not converted by thesecond color conversion layer, and a reflection preventing layerincluding a first reflection preventing portion provided over the firstblue light blocking portion to prevent reflection of external lightincident thereon, and a second reflection preventing portion over thesecond blue light blocking portion to prevent reflection of externallight incident thereon.

According to one or more example embodiments, the reflection preventinglayer may prevent reflection of a second blue light of external lightincident thereon.

According to one or more example embodiments, the reflection preventinglayer may include a plurality of layers having different reflectiveindices and stacked therein, and the reflective indices of the pluralityof layers may become greater as the respective one of the plurality oflayers is closer to the blue light blocking layer.

According to one or more example embodiments, the backlight apparatusmay emit the blue light.

According to one or more example embodiments, the blue light blockinglayer may include a plurality of first and second layers which arealternately stacked and have different reflective indices.

According to one or more example embodiments, a transmittance of theblue light blocking layer with respect to blue light may be equal to orless than 1%.

According to one or more example embodiments, the quantum dot colorfilter may further include a dispersion material layer provided in athird pixel area.

According to one or more example embodiments, the reflection preventinglayer may further include a third reflection preventing portion over thedispersion material layer and configured to prevent reflection of theexternal light incident from the outside.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates a cross-sectional schematic view of a quantum dotcolor filter according to an example embodiment;

FIG. 2 illustrates an enlarged view of a blue light blocking layer ofFIG. 1;

FIG. 3 illustrates a graph of a wavelength transmittance of the bluelight blocking layer of FIG. 2;

FIG. 4 illustrates a schematic view of a structure of a quantum dotcolor filter as a comparative sample;

FIG. 5 illustrates a view explaining a reflection preventing layer ofFIG. 1;

FIG. 6 illustrates an enlarged view of a reflection preventing layer ofFIG. 1;

FIG. 7 illustrates a cross-sectional view schematically of a quantum dotcolor filter according to an example embodiment;

FIG. 8 illustrates a cross-sectional schematic view of a quantum dotcolor filter according to an example embodiment; and

FIG. 9 illustrates a cross-sectional schematic view of a displayapparatus according to an example embodiment.

DETAILED DESCRIPTION

The present example embodiments may have different forms and should notbe construed as being limited to the descriptions set forth herein.Accordingly, the example embodiments are merely described below, byreferring to the figures, to explain aspects of the present description.

It will be understood that although the terms “first”, “second”, etc.,may be used herein to describe various components, these componentsshould not be limited by these terms. These components are only used todistinguish one component from another. As used herein, the singularforms “a,” “an” and “the” are intended to include the plural forms aswell, unless the context clearly indicates otherwise. It will be furtherunderstood that the terms “comprises” and/or “comprising” used hereinspecify the presence of stated features or components, but do notpreclude the presence or addition of one or more other features orcomponents.

Sizes of elements in the drawings may be exaggerated for convenience ofexplanation. In other words, since sizes and thicknesses of componentsin the drawings are arbitrarily illustrated for convenience ofexplanation, the following embodiments are not limited thereto. When acertain example embodiment may be implemented differently, a specificprocess order may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order.

In the following example embodiments, the x-axis, the y-axis and thez-axis are not limited to three axes of the rectangular coordinatesystem, and may be interpreted in a broader sense. For example, thex-axis, the y-axis, and the z-axis may be perpendicular to one another,or may represent different directions that are not perpendicular to oneanother.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. Expressions, such as “atleast one of,” when preceding a list of elements, modify the entire listof elements and do not modify the individual elements of the list.

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout.

FIG. 1 is a cross-sectional view schematically illustrating a quantumdot color filter 100 according to an example embodiment. FIG. 2 is anenlarged view of a blue light blocking layer 130 of FIG. 1. FIG. 3 is agraph illustrating a wavelength transmittance of the blue light blockinglayer 130 of FIG. 2.

Referring to FIG. 1, the quantum dot color filter 100 may include first,second, and third pixel areas C1, C2, and C3 that respectively generatelights of different colors. For example, when a blue light L_(B) isincident onto the quantum dot color filter 100, a red light L1 _(R), agreen light L1 _(G), and a blue light L1 _(B) may be emitted from thefirst, second, and third pixel areas C1, C2, and C3, respectively.

A first color conversion layer 140 is provided in the first pixel areaC1 and includes a plurality of quantum dots configured to convert anincident light, for example, the blue light L_(B), into a first colorlight. The first color conversion layer 140 converts the blue lightL_(B) into light having a wavelength greater than a wavelength of theblue light L_(B) and emits the converted light. The first colorconversion layer 140 may include the plurality of quantum dotsconfigured to absorb a blue light and emit a red light, for example.

A second color conversion layer 150 is provided in the second pixel areaC2 and includes a plurality of quantum dots configured to convert anincident light, for example, the blue light L_(B), into a second colorlight. The second color conversion layer 150 converts the blue lightL_(B) into light having a wavelength greater than a wavelength of theblue light L_(B) and emits the converted light. The second colorconversion layer 150 may include the plurality of quantum dotsconfigured to absorb a blue light and emit a green light, for example.

When the blue light L_(B) is incident onto the first pixel area C1, theblue light L_(B) is converted into the red light L1 _(R). Also, when theblue light L_(B) is incident onto the second pixel area C2, the bluelight L_(B) is converted into the green light L1 _(G).

Each of the plurality of quantum dots of the first and second colorconversion layers 140 and 150 may include one of nanocrystallinematerials, e.g., a silicon-based nanocrystal, a group II-VI-basedcompound semiconductor nanocrystal, a group III-V-based compoundsemiconductor nanocrystal, a group IV-VI-based compound semiconductornanocrystal, and a mixture thereof.

The group II-VI-based compound semiconductor nanocrystal may include atleast one selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe,HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe,CdZnS. CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HggZnTe,CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS,HgZnSeTe, and HgZnSTe. The group III-V-based compound semiconductornanocrystal may include at least one selected from GaN, GaP, GaAs, AlN,AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP,InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs,InAlNP, InAlNAs, and InAlPAs. The group IV-VI-based compoundsemiconductor nanocrystal may include SbTe, for example.

Even if the quantum dots of the first and second color conversion layers140 and 150 include the same material, light emitted from the respectivefirst and second color conversion layers 140 and 150 have differentwavelengths from each other according to sizes of the quantum dots ofthe first and second color conversion layers 140 and 150. The smaller asize of a quantum dot, the shorter a wavelength of the light emittedfrom the quantum dot. Accordingly, light of different visible colors maybe emitted by adjusting sizes of the quantum dots of the first andsecond color conversion layers 140 and 150.

In order to emit red light from the first color conversion layer 140 andto emit green light from the second color conversion layer 50, thematerials of the quantum dots of the first and second color conversionlayers 140 and 150 may be the same, but the size of the quantum dots ofthe first color conversion layer 140 may be greater than the size of thequantum dots of the second color conversion layer 150.

A dispersion material layer 160 may be in the third pixel area C3 todisperse the incident light. The dispersion material layer 160 transmitslight, i.e., the blue light L_(B), without conversion thereof such thatnon-converted blue light L1 _(B) is emitted from the dispersion materiallayer 160.

The dispersion material layer 160 may include titanium oxide TiO₂.However, the dispersion material layer 160 is not limited thereto. Thedispersion material layer 160 may include at least one of variousmaterials as long as the material does not convert, but simplydisperses, the incident light.

The first, second, and third pixel areas C1, C2, and C3 may be separatedfrom each other by partitions 120 disposed over a transparent substrate110. The partitions 120 may include a black matrix to avoid color mixingamong the first, second, and third pixel areas C1, C2, and C3.

A blue light blocking layer 130 may be provided over the first andsecond color conversion layers 140 and 150 and may block emission of theblue light L_(B) which has not been converted by the first and secondcolor conversion layers 140 and 150. The blue light blocking layer 130may include a first blue light blocking portion 131 disposed over thefirst color conversion layer 140 and a second blue light blockingportion 132 disposed over the second color conversion layer 150.

The first blue light blocking layer 131 transmits the red light L1 _(R)converted from the blue light L_(B) by the first color conversion layer140 and blocks the blue light L_(B) which has not been converted by thefirst color conversion layer 140. The second blue light blocking layer132 transmits the green light L1 _(G) converted by the second colorconversion layer 150 and blocks the blue light L_(B) which has not beenconverted by the second color conversion layer 150.

The blue light blocking layer 130 has a low transmittance with respectto the blue light L_(B) and a high transmittance with respect to theother visible light. For example, a transmittance of the blue lightblocking layer 130 with respect to a blue light having a wavelength ofabout 466 nm may be less than 1%, and a transmittance of the blue lightblocking layer 130 with respect to the other light of a wavelengthlonger than 530 nm may be greater than 50%, as illustrated in FIG. 3.

The blue light blocking layer 130 may have a stack structure including aplurality of layers that have different refractive indices from oneanother and are alternately stacked. Referring to FIG. 2, the blue lightblocking layer 130 may have a stack structure in which first and secondlayers 130 a and 130 b respectively having different refractive indicesare alternately stacked. However, a structure of the blue light blockinglayer 130 is not limited thereto. The blue light blocking layer 130 mayhave various structures as long as the structure of the blue lightblocking layer 130 includes a plurality of layers which are alternatelystacked therein. For example, the structure of the blue light blockinglayer 130 may include more than three layers which are alternatelystacked therein.

The first layer 130 a and the second layer 130 b may include atransparent material. For example, the first layer 130 a may includesilicon oxide SiO₂, and the second layer 130 b may include siliconnitride SiN_(x). The first layer 130 a and the second layer 130 b may beformed via a chemical vapor deposition (CVD) method. However, thepresent disclosure is not limited thereto, and thus, the first layer 130a and the second layer 130 b may be formed via other deposition methods.

As described above, the blue light blocking layer 130 selectivelytransmits light which enters thereinto and, thus, improves a colorreproduction characteristic of the quantum dot color filter 100.

However, since the blue light blocking layer 130 has a stack structurein which a plurality of layer having different refractive indices arerepeatedly stacked, the blue light blocking layer 130 has a firstblocking characteristic for light traveling from a first side, e.g., aninside, to an opposite second side, e.g., outside thereof, and a secondblocking characteristic for light traveling from the second side to thefirst side. Accordingly, external light which enters the second side ofthe blue light blocking layer 130 may be unintentionally reflected. Forexample, the blue light blocking layer 130 may reflect the externallight, e.g., blue light, which enters from the second side.

FIG. 4 is a view schematically illustrating a structure of a quantum dotcolor filter 10 as a comparative sample. Referring to FIG. 4, anexternal light may be visible light including red light L0 _(R), greenlight L0 _(G), and blue light L0 _(B). The external light may beintroduced to the color filter 10 through the transparent substrate 110,such that it is incident on the second surface of the blue lightblocking layer 130.

The external light, such as the red light L0 _(R) and a green light L0_(G), may not be reflected by the blue light blocking layer 130, butmost of the blue light L0 _(B) may be reflected by the blue lightblocking layer 130. For example, more than about 50% of the externallight, such as the red light L0 _(R) and a green light L0 _(G), may betransmitted through the blue light blocking layer 130, and more thanabout 99% of the blue light L0 _(B) may be reflected by the blue lightblocking layer 130. Accordingly, the red light L1 _(R) transmittedthrough the first blue light blocking portion 131 may be mixed with thereflected blue light L0 _(B) in the first pixel area C1. Also, the greenlight L1 _(G) transmitted through the second blue light blocking portion132 may be mixed with the reflected blue light L0 _(B) in the secondpixel area C2. Therefore, the mixing may cause a low color reproductioncharacteristic.

Referring back to FIG. 1, considering the above-described mixing, in thequantum dot color filter 100 according to an embodiment, a reflectionpreventing layer 170 may be disposed over the blue light blocking layer130.

FIG. 5 is a view explaining the reflection preventing layer 170 of FIG.1 and FIG. 6 is an enlarged view of the reflection preventing layer 170of FIG. 1. Referring to FIG. 5, the reflection preventing layer 170 mayinclude a first reflection preventing portion 171 disposed over thefirst blue light blocking portion 131 and a second reflection preventingportion 172 disposed over the second blue light blocking portion 132.

The first and second reflection preventing portions 171 and 172 of thereflection preventing layer 170 may be disposed on the transparentsubstrate 110. For example, the first reflection preventing portion 171may be disposed between the transparent substrate 110 and the first bluelight blocking portion 131, and the second reflection preventing portion172 may be disposed between the transparent substrate 110 and the secondblue light blocking portion 132.

The reflection preventing layer 170 may prevent reflection of the bluelight L0 _(B) of the external light which is incident from an outsidethereof. The reflection preventing layer 170 may not reflect, but mayabsorb the red light L0 _(R), the green light L0 _(G), and the bluelight L0 _(B) of the external light. Accordingly, since the externallight is not reflected, the external light is prevented from being mixedwith the red light L1 _(R) and the green light L1 _(G) which are emittedfrom the first and second color conversion layers 140 and 150,respectively.

In the first pixel area C1, the external light is absorbed by thereflection preventing layer 170, the first blue light blocking portion131, and/or or the first color conversion layer 140. Accordingly, thered light L1 _(R) converted by the first color conversion layer 140passes through the first blue blocking portion 131 and the reflectionpreventing layer 170 to be transmitted to the outside, without beingeffected by the reflected external light.

In the second pixel area C2, the external light is absorbed by thereflection preventing layer 170, second blue light blocking portion 132,and/or the second color conversion layer 150. Accordingly, the greenlight L1 _(G) converted by the second color conversion layer 150 passesthrough the second blue blocking portion 132 and the reflectionpreventing layer 170 to be transmitted to the outside, without beingeffected by the reflected external light.

Referring to FIGS. 5 and 6, the reflection preventing layer 170 mayinclude a plurality of layers 170 a, 170 b, 170 c, 170 d, 170 e, and 170f having reflective indices different from one another. The reflectiveindices of the plurality of layers 170 a, 170 b, 170 c, 170 d, 170 e,and 180 f become greater from the outside to the inside thereof, i.e.,may increase from the substrate 110 to the pixel areas.

The reflective indices of the plurality of layers 170 a, 170 b, 170 c,170 d, 170 e, and 170 f of the reflection preventing layer 170 graduallyincrease from the outside to the inside. For example, the reflectiveindices of the plurality of layers 170 a, 170 b, 170 c, 170 d, 170 e,and 170 f of the reflection preventing layer 170 increase as theplurality of layers 170 a, 170 b, 170 c, 170 d, 170 e, and 170 f of thereflection preventing layer 170 are further away from the transparentsubstrate 110. The reflective indices of the plurality of layers 170 a,170 b, 170 c, 170 d, 170 e, and 170 f of the reflection preventing layer170 may increase as the plurality of layers 170 a, 170 b, 170 c, 170 d,170 e, and 170 f of the reflection preventing layer 170 are closer tothe blue light blocking layer 130.

The plurality of layers 170 a, 170 b, 170 c, 170 d, 170 e, and 170 f mayinclude at least one of silicon oxide, silicon nitride, or siliconnitride oxide. For example, the layers 170 a, 170 b, and 170 c adjacentto the blue light blocking layer 130 may include silicon nitride, thelayer 170 g adjacent to the transparent substrate 110 may includesilicon oxide, and the layers 170 d, 170 e, and 170 f between the layers170 a, 170 b, and 170 c, and the layer 170 g, may include siliconnitride oxide.

However, the number, materials, and reflective indices of the pluralityof layers 170 a, 170 b, 170 c, 170 d, 170 e, and 170 f of the reflectionpreventing layer 170, i.e., the first reflection preventing portion 171and the second reflection preventing portion 172, are illustrated as anexample. If the reflective indices of the plurality of layers 170 a, 170b, 170 c, 170 d, 170 e, and 170 f become greater from the outside to theinside thereof, at least one of the number, the materials, and thereflective indices may be changed.

Meanwhile, referring to FIGS. 1 and 5, the reflection preventing layer170 may further include a third reflection preventing portion 173disposed over the dispersion material layer 160. The third reflectionpreventing portion 173 of the reflection preventing layer 170 mayinclude the plurality of layers 170 a, 170 b, 170 c, 170 d, 170 e, and170 f of different reflective indices, respectively. The reflectionindices of the plurality of layers 170 a, 170 b, 170 c, 170 d, 170 e,and 170 f of the reflection preventing layer 170 become greater from theoutside to the inside. For example, the reflective indices of theplurality of layers 170 a, 170 b, 170 c, 170 d, 170 e, and 170 f of thereflection preventing layer 170 gradually increase from the outside tothe inside.

A structure and a material of the third reflection preventing portion173 of the reflection preventing layer 170 may be same as the structureand the material of the first reflection preventing portion 171 and thesecond reflection preventing portion 172. Accordingly, the thirdreflection preventing portion 173 may be simultaneously formed when thefirst and second reflection preventing portions 171 and 172 are formed.

Since the third reflection preventing portion 173 prevents reflection ofthe external light which is incident from the outside, decrease of acolor reproduction characteristic may be reduced or prevented.Accordingly, in the third pixel area C3, the blue light L1 _(B)dispersed by the dispersion material layer 160 passes through thereflection preventing layer 170 and then is emitted outside. Theexternal light is absorbed by the third reflection preventing portion173 and/or the dispersion material layer 160.

While the reflection preventing layer 170 is shown in FIGS. 1 and 5 isthe transparent substrate 110 and is directly on the blue light blockinglayer 130 or the dispersion material layer 160, embodiments are notlimited thereto. As illustrated in FIG. 7, the reflection preventinglayer 170 may be above the transparent substrate 110 in the quantum dotcolor filter 100A. In this case, the reflection preventing layer 170 andthe blue light blocking layer 130 may be spaced apart from each other,and the reflection preventing layer 170 and the dispersion materiallayer 160 may be spaced apart from each other. Further, whileillustrated as separate reflection prevention layers 171, 172, 173,i.e., are spaced apart from one another on the transparent substrate110, the reflection preventing layer 170 may be provided as a singlelayer on the exterior of the substrate 110 to overlap all of the pixelareas C1 to C3.

Also, in the above described embodiment, the quantum dot color filter100 includes a plurality of pixel areas, that is, the first throughthird pixel areas C1, C2, and C3. However, this is illustrative. Aquantum dot color filter may include first through fourth pixel areasC1, C2, C3, and C4 as illustrated in FIG. 8.

FIG. 8 is a cross-sectional view schematically illustrating a quantumdot color filter 200 according to an embodiment. Referring to FIG. 8,the quantum dot color filter 200 includes the first through fourth pixelareas C1, C2, C3, and C4, which output different colors from oneanother. The first through fourth pixel areas C1, C2, C3, and C4 may beseparated from one another by partitions 220 disposed over a transparentsubstrate 210. For example, when a blue light L_(B) is incident on thequantum dot color filter 200, a red light L1 _(R), a white light L1_(w), a green light L1 ₆, and a blue light L1 _(B) may be respectivelyemitted from the first through fourth pixel areas C1, C2, C3, and C4.

A first color conversion layer 240 in the first pixel area C1 mayinclude a plurality of quantum dots configured to convert an incidentlight into a first color light. The first color conversion layer 240 mayconvert the incident light into light having a wavelength longer than awavelength of the incident light and then emit the converter light. Thefirst color conversion layer 240 may include the plurality of quantumdots configured to absorb the blue light L_(B) and emit the red light L1_(R), for example.

A fourth color conversion layer 245 in the second pixel area C2 mayinclude a plurality of quantum dots configured to convert an incidentlight into a fourth color light. The fourth color conversion layer 245may convert a portion of the incident light into light having awavelength longer than a wavelength of the incident light. The fourthcolor conversion layer 245 may convert a portion of the incident bluelight L_(B) into the red light L1 _(R) and may convert another portionof the incident blue light L_(B) into the green light L1 _(G), whileallowing some of the light to remain unconverted. Accordingly, in thefourth color conversion layer 245, the blue light L1 _(B), which is notconverted, and the red light L1 _(R) and the green light L1 _(G), whichare converted, are mixed and then the white light L1 _(w) may beemitted.

A second color conversion layer 250 in the third pixel area C3 mayinclude a plurality of quantum dots configured to convert an incidentlight into a second color light. The second color conversion layer 250may convert the incident light into light having a wavelength longerthan a wavelength of the incident light and then emit the convertedlight. The second color conversion layer 250 may include the pluralityof quantum dots configured to absorb the blue light L_(B) and emit thegreen light L1 _(G), for example.

The plurality of quantum dots of the first, second, and fourth colorconversion layers 240, 250, and 245 may include one of nanocrystallinematerials, e.g., a silicon-based nanocrystal, a group II-VI-basedcompound semiconductor nanocrystal, a group III-V-based compoundsemiconductor nanocrystal, a group IV-VI-based compound semiconductornanocrystal, and a mixture thereof.

The group II-VI-based compound semiconductor nanocrystal may include atleast one selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe,HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe,CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HggZnTe,CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS,HgZnSeTe, and HgZnSTe. The group III-V-based compound semiconductornanocrystal may include at least one selected from GaN, GaP, GaAs, AlN,AlP, AlAs, InN, InP, InAs, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP,InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs,InAlNP, InAlNAs, and InAlPAs. The group IV-VI-based compoundsemiconductor nanocrystal may include SbTe, for example.

Even if the quantum dots of the first, second, fourth color conversionlayers 240, 250, and 245 include the same material, emitting lightsinclude different wavelengths from each other according to sizes of thequantum dots. The smaller a size of a quantum dot, the shorter awavelength of the emitting light. Accordingly, lights of differentvisible spectrums may be emitted by adjusting sizes of the quantum dotsof the first, second, and fourth color conversion layers 240, 250, and245.

When red light is generated from the first color conversion layer 240and green light is generated from the second color conversion layer 250,the materials of the quantum dots of the first and second colorconversion layers 240 and 250 may be same, but the size of the quantumdots of the first color conversion layer 240 may be greater than thesize of the quantum dots of the second color conversion layer 250.

A dispersion material layer 260 may be in the fourth pixel area C4 todisperse the incident light. The dispersion material layer 260 does notconvert the incident blue light L_(B) to generate non-converted bluelight L1 _(B). The dispersion material layer 260 may include titaniumoxide TiO₂. However, the material of the dispersion material layer 260is not limited thereto. The dispersion material layer 260 may include atleast one of various materials as long as the material does not convertbut merely disperses the incident light.

A blue light blocking layer 230 may be disposed over the first andsecond color conversion layers 240 and 250 and may block emission of theblue light L_(B) which has not been converted in the first and secondcolor conversion layers 240 and 250. The blue light blocking layer 230may include a first blue light blocking portion 231 disposed over thefirst color conversion layer 240 and a second blue light blockingportion 232 disposed over the second color conversion layer 250.

A reflection preventing layer 270 may be disposed over the blue lightblocking layer 230. The reflection preventing layer 270 may include afirst reflection preventing layer 271 disposed over the first blue lightblocking portion 231, and a second reflection preventing layer 271disposed over the second blur light blocking portion 231. The reflectionpreventing layer 270 may further include a third reflection preventingportion 273 disposed over the dispersion material layer 260, and afourth reflection preventing portion 274 disposed over the fourth colorconversion layer 245.

The reflection preventing layer 270 may include the plurality of layers170 a, 170 b, 170 c, 170 d, 170 e, and 170 f respectively havingdifferent reflective indices. The reflective indices of the plurality oflayers 170 a, 170 b, 170 c, 170 d, 170 e, and 170 f become greater fromthe outside to an inside thereof.

The reflective indices of the plurality of layers 170 a, 170 b, 170 c,170 d, 170 e, and 170 f of the reflection preventing layer 270 graduallyincrease from the outside to the inside. The plurality of layers 170 a,170 b, 170 c, 170 d, 170 e, and 170 f may include at least one ofsilicon oxide, silicon nitride, or silicon nitride oxide.

FIG. 9 is a cross-sectional view schematically illustrating a displayapparatus 1000 according to an embodiment.

The display apparatus 1000 includes a backlight apparatus 1100, a liquidcrystal panel disposed over the backlight apparatus 1100, and a quantumdot color filter 1600 disposed over the liquid crystal panel. Thebacklight apparatus 1100 provides the liquid crystal panel with lightusable to form an image. The liquid crystal panel may include a lowersubstrate 1200 and an upper substrate 1400, which face each other, and aliquid crystal layer 1300 between the lower substrate 1200 and the uppersubstrate 1400. The quantum dot color filter 1600 may change awavelength of light emitted from the backlight apparatus 1100 and passedthrough the liquid crystal panel, to form a color.

The backlight apparatus 1100 may include a light source to generate bluelight L_(B) and provide the generated blue light to the liquid crystalpanel.

The lower substrate 1200 may include a first substrate 1220, a lowerpolarization plate 1210 below the first substrate 1220, and a pixelelectrode 1240 above the first substrate 1220. A thin film transistor(TFT) array layer 1230 may be between the first substrate 1220 and thepixel electrode 1240, and includes a plurality of transistors (notillustrated) to controls areas of the liquid crystal layer 1300 whichrespectively correspond to pixels.

The first substrate 1220 may include a glass material or a transparentplastic material. The lower polarization plate 1210 transmits only lighthaving a particular polarization. For example, the lower polarizationplate 1210 may transmit light linearly polarized in a first direction.

The TFT array layer 1230 may include the plurality of transistors and agate wiring and a data wiring which are configured to respectively applya gate signal and a data signal to each of the plurality of transistors.The pixel electrode 1240 is connected to a drain electrode of thetransistor of the TFT array layer 1230 and receives a data voltage fromthe drain electrode.

The upper substrate 1400 may include a second substrate 1420, an upperpolarization plate 1410 disposed above the second substrate 1420, and acommon electrode 1430 disposed below the second substrate 1420.

The upper polarization plate 1410 transmits only light having aparticular polarization. For example, the upper polarization plate 1410may transmit light linearly polarized in a second directionperpendicular to the first direction. However, the present disclosure isnot limited thereto. The upper polarization plate 1410 and the lowerpolarization plate 1210 may be a same polarization plate configured totransmit light of a same polarization.

The liquid crystal layer 1300 between the upper substrate 1400 and thelower substrate 1200 may control arrangement of liquid crystal moleculesincluded in the liquid crystal layer 1300 according to a voltage appliedbetween the common electrode 1430 and the pixel electrode 1240. That is,according to the voltage applied between the common electrode 1430 andthe pixel electrode 1240, an area of the liquid crystal layer 1300between the common electrode 1430 and the pixel electrode 1240 iscontrolled between an on-mode, in which polarization of an incidentlight is changed, and an off-mode, in which polarization of the incidentlight is not changed. Also, a degree of the changed polarization of theincident light may be adjusted to output intermediate gradations.

The quantum dot color filter 1600 include a transparent substrate1610,first through third pixel areas C1, C2, and C3, and partitions 1620 toseparate the first through third pixel areas C1, C2, and C3 from eachother.

The first through third pixel areas C1, C2, and C3 respectively displayred, green, and blue as described above. The first pixel area C1includes a first color conversion layer 1640 configured to convert ablue light L₁₃ into a red light, the second pixel area C2 includes asecond color conversion layer 1650 configured to convert the blue lightL_(B) into a green light, and the third pixel area C2 includes adispersion material layer 1660.

The first and second color conversion layers 1640 and 1650 may include ablue light blocking layer 1630 configured to block emission of the bluelight L_(B), which is not converted by the first and second colorconversion layers 1640 and 1650. The blue light blocking layer 1630 mayinclude a first blue light blocking portion 1631 disposed over the firstcolor conversion layer 1630 and a second blue light blocking portion1632 disposed over the second color conversion layer 1650.

The first blue light blocking portion 1631 transmits the red light,which is converted by the first color conversion layer 1640, and blocksthe blue light L_(B), which is not converted by the first colorconversion layer 1640. The second blue light blocking portion 1632transmits the green light, which is converted by the second colorconversion layer 1650, and blocks the blue light L_(B), which is notconverted by the second color conversion layer 1650.

The color filter 1600 may include a reflection preventing layer over ablue light blocking layer and may prevent reflection of an externallight incident from outside. The reflection preventing layer may bedisposed over a dispersion material layer.

A reflection preventing layer 1670 may be disposed over the blue lightblocking layer 1630. The reflection preventing layer 1670 may include afirst reflection preventing layer 1671 disposed over the blue lightblocking portion 1631 and a second reflection preventing portion 1672disposed over the second blue light blocking portion 1632. Thereflection preventing layer 1670 may further include a third reflectionpreventing portion 1673 disposed over the dispersion material layer1660.

The blue light L_(B) is emitted from the backlight apparatus 1100,passes through the liquid crystal panel, is on or off in the respectivepixel areas according to image information, enters into the quantum dotcolor filter 1600, and is converted into a red light, a green light, anda blue light so that an image is displayed. Here, since the reflectionpreventing layer 1670 prevents reflection of the external light, a colorreproduction characteristic is improved.

Meanwhile, in the above-described embodiment, a case, in which thebacklight apparatus 1100 emits the blue light L_(B), is explained.However, the present disclosure is not limited thereto. The backlightapparatus 1100 may include one of various backlight apparatuses as longas a quantum dot characteristic of a quantum dot color filter is changedto convert an incident light into a different color to be irradiated.For example, the backlight apparatus may irradiate an ultraviolet light.

As described above, in the quantum dot color filter, the blue lightblocking layer blocks emission of the blue light, which is not convertedby the color conversion layer, and the reflection preventing layerprevents reflection of an external light by the blue light blockinglayer. The display apparatus including the quantum dot color filterwhich is described above, may improve color reproduction.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A display apparatus, comprising: a backlight; aliquid crystal panel on the backlight; and a quantum dot color filter onthe liquid crystal panel, wherein the quantum dot color filter includes:a first color conversion layer in a first pixel area and including aplurality of quantum dots to convert incident light into a first colorlight; a second color conversion layer in a second pixel area andincluding a plurality of quantum dots to convert incident light into asecond color light; a blue light blocking layer including a first bluelight blocking portion over the first color conversion layer to blockemission of a blue light of the incident light which is not converted bythe first color conversion layer, and a second blue light blockingportion over the second color conversion layer to block emission of theblue light of the incident light which is not converted by the secondcolor conversion layer; and a reflection preventing layer including afirst reflection preventing portion over the first blue light blockingportion to prevent reflection of external light incident thereon, and asecond reflection preventing portion on the second blue light blockingportion to prevent reflection of external light incident thereon.
 2. Thedisplay apparatus as claimed in claim 1, wherein the reflectionpreventing layer prevents reflection of blue light of external lightincident thereon.
 3. The display apparatus as claimed in claim 1,wherein: the reflection preventing layer includes a plurality of stackedlayers that have different reflective indices from one another; and thereflective indices of the plurality of stacked layers increase towardsthe blue light blocking layer.
 4. The display apparatus as claimed inclaim 1, wherein the backlight emits blue light to be blocked by theblue light blocking layer.
 5. The display apparatus as claimed in claim4, wherein the blue light blocking layer includes a plurality ofalternately stacked first and second layers that have differentreflective indices from one another.
 6. The display apparatus as claimedin claim 4, wherein a transmittance of the blue light blocking layerwith respect to the blue light emitted from the backlight is equal to orless than 1%.
 7. The display apparatus as claimed in claim 1, whereinthe quantum dot color filter further includes a dispersion materiallayer provided in a third pixel area.
 8. The display apparatus asclaimed in claim 7, wherein the reflection preventing layer furtherincludes a third reflection preventing portion over the dispersionmaterial layer to prevent reflection of an external light incident fromthe outside thereof.
 9. The display apparatus as claimed in claim 1,further comprising: a transparent substrate on the quantum dot colorfilter, wherein the first reflection preventing portion of thereflection preventing layer is between the transparent substrate and thefirst blue light blocking portion, and the second reflection preventingportion of the reflection preventing layer is between the transparentsubstrate and the second blue light blocking portion.
 10. The displayapparatus as claimed in claim 1, further comprising: a transparentsubstrate on the quantum dot color filter, wherein the transparentsubstrate is between the first reflection preventing portion and thefirst blue light blocking portion, and between the second reflectionpreventing portion of is between the transparent substrate and thesecond blue light blocking portion.
 11. The display apparatus as claimedin claim 10, wherein the first reflection preventing portion and thesecond reflection preventing portion are spaced apart from one another.12. A quantum dot color filter, comprising: a first color conversionlayer in a first pixel area and including a plurality of quantum dots toconvert incident light into a first color light; a second colorconversion layer in a second pixel area, and including a plurality ofquantum dots to convert incident light into a second color light; a bluelight blocking layer including a first blue light blocking portion onthe first color conversion layer to block emission of first blue lightof the incident light which is not converted by the first colorconversion layer, and a second blue light blocking portion on the secondcolor conversion layer to block emission of first blue light of theincident light which is not converted by the second color conversionlayer; and a reflection preventing layer including a first reflectionpreventing portion provided over the first blue light blocking portionto prevent reflection of an external light, and a second reflectionpreventing portion provided over the second blue light blocking portionto prevent reflection of external light.
 13. The quantum dot colorfilter as claimed in claim 12, wherein the reflection preventing layerprevents reflection of a second blue light, different from the firstblue light, of external light.
 14. The quantum dot color filter asclaimed in claim 12, wherein: the reflection preventing layer includes aplurality of stacked layers that have different reflective indices fromone another; and the reflective indices of the plurality of stackedlayers increase towards the blue light blocking layer.
 15. The quantumdot color filter as claimed in claim 12, wherein the blue light blockinglayer includes a plurality of first and second layers which arealternately stacked and have different reflective indices from oneanother.
 16. The quantum dot color filter as claimed in claim 12,wherein a transmittance of the blue light blocking layer with respect tothe first blue light is equal to or less than 1%.
 17. The quantum dotcolor filter as claimed in claim 12, wherein the quantum dot colorfilter further includes a dispersion material layer in a third pixelarea.
 18. The quantum dot color filter as claimed in claim 17, whereinthe reflection preventing layer further includes a third reflectionpreventing portion disposed over the dispersion material layer toprevent reflection of external light incident.
 19. The quantum dot colorfilter as claimed in claim 12, further comprising: a transparentsubstrate, wherein the first reflection preventing portion of thereflection preventing layer is between the transparent substrate and thefirst blue light blocking portion, and the second reflection preventingportion of the reflection preventing layer is between the transparentsubstrate and the second blue light blocking portion.
 20. The quantumdot color filter as claimed in claim 12, further comprising: atransparent substrate, wherein the transparent substrate is between thefirst reflection preventing portion and the first blue light blockingportion, and between the second reflection preventing portion of isbetween the transparent substrate and the second blue light blockingportion.